Device for a hydraulic system, hydraulic system, drive module of a motor vehicle

Abstract

The invention relates to a device (31) for a hydraulic system (1), in particular of a motor vehicle, with a first hydraulic line (20), which can be connected on one side to a hydraulic pressure source and on the other side to at least one apparatus to be cooled and / or lubricated, wherein a pressure limitation valve (22) is allocated to the first hydraulic line (20), which pressure limitation valve has a tank connection and connects the first hydraulic valve (20) to the tank connection when a hydraulic pressure in the first hydraulic line (20) exceeds a predefined limit value, wherein downstream of the pressure limitation valve (22) an aperture (23) is arranged in the first hydraulic line (20), and wherein downstream of the aperture (23) a throttle (30) is arranged or formed in the first hydraulic line (20). The invention also relates to a hydraulic system (1) having such a device (31) and to a drive module having such a hydraulic system (1).

Description

[0001] The invention relates to a device for a hydraulic system and a hydraulic system with such a device, in particular for a drive module of a motor vehicle. The invention also relates to a drive module with such a hydraulic system.

[0002] Hydraulic systems for motor vehicle drive modules are known from the prior art, which include hydraulic circuits for cooling and / or lubricating clutches and drive motors. In particular, drive modules for hybrid vehicles are known, which have an internal combustion engine and an electric motor for selectively powering the vehicle. Such drive modules typically have clutches for disconnecting and connecting the electric motor of the internal combustion engine to a drive train of the vehicle. Cooling and lubricating oil, which circulates in cooling circuits, is required to cool and lubricate the clutches and the electric motor itself.The drive module typically has separate cooling circuits for the clutches, with at least one pump, usually electrically driven, for adjusting the cooling fluid flow to each clutch associated with the electric motor and one or more clutches associated with the internal combustion engine. The at least two pumps are usually controlled by a control unit, with the cooling fluid flow being adjusted particularly as a function of the pump speed.

[0003] Document CN 110 285 211 A relates to a lubrication system for a coal mining machine. The lubrication system has an oil inlet channel and an oil return channel, wherein the oil inlet channel includes an oil tank, a hydraulic pump, a reversing valve, a throttle valve and oil lines, wherein the oil tank, the hydraulic pump, the reversing valve and the throttle valve are connected sequentially via the oil lines, and wherein the hydraulic pump, the reversing valve and the throttle valve are arranged in the oil tank.

[0004] The prior art documents DE 198 13 982 A1 and DE 100 30 838 A1 are also known.

[0005] The invention is based on the objective of creating an improved hydraulic system that has reduced complexity.

[0006] The problem underlying the invention is solved by a device for a hydraulic system with the features of claim 1. A device is provided comprising a first hydraulic line that can be connected to a hydraulic pressure source on the one hand and to at least one device to be cooled and / or lubricated on the other hand, wherein a pressure relief valve is associated with the first hydraulic line, which has a tank connection and connects the first hydraulic line to the tank connection when a hydraulic pressure in the first hydraulic line exceeds a predetermined limit, wherein an orifice is arranged in the first hydraulic line downstream of the pressure relief valve, and wherein a throttle is arranged or formed in the first hydraulic line downstream of the orifice.The claimed combination and arrangement of pressure relief valve, orifice, and throttle achieves an advantageous dependence of the flow rate of a medium flowing through the first hydraulic line to the device on the medium's temperature, as will be explained below. The pressure relief valve offers the advantage that the flow rate of a liquid medium flowing through the first hydraulic line to the device is limited as needed. If the flow rate is too high, excess medium is preferably returned directly to a reservoir supplying the medium. The suction reliability and function of the hydraulic system are maintained without, for example, having to increase the quantity of medium in the hydraulic system because the excess medium is returned to the reservoir.The pressure relief valve preferably has such a large flow cross-section that the pressure upstream of the valve is not, or at least only minimally, affected by the pressure drop of the flowing medium and the medium's temperature. The orifice further ensures a particularly advantageous, demand-based supply of medium to the device. The flow rate of an ideal orifice is determined solely by the pressure drop across the orifice and is not, or only minimally, dependent on the temperature of the flowing medium. Preferably, the orifice is designed as a thin-walled component. By designing the orifice in this way as a thin-walled component, its actual behavior advantageously corresponds to, or at least approximates, that of an ideal orifice.The combination of such a pressure relief valve with a nearly constant opening pressure upstream of such an orifice plate and a temperature-dependent back pressure from the downstream section after the orifice plate towards the throttle plate results in a temperature-dependent differential pressure at the orifice plate and thus a temperature-dependent media flow to the device, thereby achieving a temperature-dependent supply to the device. Together with the throttle plate, the pressure relief valve and the orifice plate are thus designed to regulate the volumetric flow rate of the medium to the device depending on the temperature of the cooling medium, thereby achieving a temperature-dependent supply of medium to the device without the need for complex control systems.In particular, it is provided that, when supplying the device with medium on demand, less medium is supplied at cold temperatures and more medium at high temperatures. Preferably, the throttle is designed as a temperature- and flow-dependent hydraulic resistance through the flow resistances of the downstream section leading to the device. Specifically, the throttle is formed by hydraulic lines leading to the device that act like a throttle. The temperature-dependent supply of the device functions, for example, as follows: the volumetric flow rate through the ideal orifice is independent of the viscosity of the medium and is determined solely by the geometry of the orifice, in particular its diameter. If the actual orifice, as described above, is designed with the thinnest possible walls, its behavior corresponds at least largely to that of the ideal orifice.In contrast, the volumetric flow rate through the throttle is not only dependent on the geometry of the throttled section, but also strongly dependent on the viscosity of the medium at a constant pressure upstream of the throttle. The colder the medium, the higher its viscosity and the lower the volumetric flow rate through the throttle. Therefore, less medium flows to the device at low temperatures than at high temperatures. Furthermore, the volumetric flow rate depends solely on the release pressure of the pressure relief valve. The higher this pressure, the higher the respective maximum volumetric flow rate. The advantageous effect—a temperature- and thus viscosity-dependent media flow—results automatically from the arrangement of the three components. The geometry of the orifice and throttle, as well as the release pressure of the pressure relief valve, are preferably coordinated such that a predetermined, temperature-dependent media flow is supplied to the device.The orifice diameter is specifically chosen to ensure a sufficiently high flow rate for cooling when the medium is hot, for example, 100 °C. Simultaneously, the throttling section allows only a small flow rate for lubrication when the medium is cold, for example, -30 °C. The release pressure of the pressure relief valve is preferably chosen to be as low as possible or minimized to such an extent that the pressure relief valve still functions robustly, for example, to keep the energy consumption of a media source as low as possible. Appropriate simulations and model calculations are performed, in particular, for the corresponding adjustment and optimization of the throttling section, orifice, and release pressure.

[0007] According to a preferred embodiment of the invention, the device comprises at least one cooling and / or lubricating element, and the element, or at least one of the elements, is a clutch and / or a drive motor for a motor vehicle. With such elements, the advantages achieved by the device according to the invention are particularly pronounced.

[0008] It is particularly preferred that the pressure relief valve be designed as a poppet valve. Designing the pressure relief valve as a poppet valve provides a particularly advantageous and robust method for limiting the flow of the medium. Furthermore, poppet valves practically do not impede the flow when not actuated. In poppet valves, the valve is opened by displacing a sealing element against the spring force of a spring element. The opening pressure is thus determined by the spring force. Moreover, such poppet valves are also particularly robust against dirt particles because they have significantly larger gaps for the bearing of the sealing element, so that the arrangement consisting of such a pressure relief valve and the orifice can be positioned near a reservoir in which dirt particles can accumulate. Preferably, the arrangement is made of plastic.In particular, apart from the spring and seals, it is made entirely of plastic and is therefore advantageous in terms of weight, corrosion, manufacturability and manufacturing costs.

[0009] According to a preferred embodiment of the invention, the pressure relief valve and the orifice are designed as a single module. This design as a single module offers a particularly advantageous way to easily replace a conventional pump arrangement as described above. For example, one of the hydraulic systems mentioned above can be converted particularly easily. The module is preferably designed as a single structural unit, making it advantageously easy to replace.

[0010] It is particularly preferred that a tubular, and especially a conical, adapter element is arranged downstream of the orifice as part of the throttle in the first hydraulic line. The adapter element, and in particular its suitable geometric design, provides an advantageous additional means of influencing the throttle section and thus the throttle's properties. The throttle is therefore advantageously adapted to the cooling and / or lubrication requirements of the device. The adapter element is specifically designed to connect the device to the hydraulic lines leading to it. The adapter element preferably has a first open end associated with the orifice, with a first cross-section, and a second open end associated with the hydraulic lines, with a second cross-section. In particular, the second cross-section is smaller than the first.The adapter element is advantageously designed with a conical shape, i.e., it has a conical basic form. By appropriately selecting the second cross-section, a conveniently simple adaptation of the device to hydraulic lines with corresponding cross-sections is ensured.

[0011] The hydraulic system with the features of claim 6 comprises at least one device to be cooled and / or lubricated and a hydraulic circuit for cooling and / or lubricating the device, wherein the hydraulic circuit comprises at least one hydraulic pressure source, in particular a pump, for conveying a liquid medium. The hydraulic system is characterized by a device according to the invention, which includes the first hydraulic line and which is connected to the hydraulic pressure source on the one hand and to the at least one device on the other. The advantages already mentioned also result from this.

[0012] The hydraulic system preferably comprises a first clutch, a second clutch, and a third clutch as devices to be cooled and / or lubricated, wherein the first and second clutches are assigned to a first drive engine, in particular an internal combustion engine, and the third clutch to a second drive engine, in particular an electric motor, in order to selectively couple them to a transmission of the motor vehicle, wherein the hydraulic circuit is designed for cooling and / or lubricating at least the clutches and the second drive engine, and wherein the hydraulic circuit includes at least one controllable valve interposed between the clutches and the hydraulic pressure source, in particular a pump, for adjusting a fluid flow at least for the clutches and the second drive engine. The valve is thus designed to select at least the clutches and the drive engine through which the fluid flows.This eliminates the need for an additional pump for the third coupling, thus advantageously reducing the complexity of the hydraulic system compared to the aforementioned systems, which have at least two separate pumps for the couplings. The function of the pump assigned to the third coupling is therefore taken over by a common pump for all three couplings. For this purpose, an additional hydraulic interface is created, particularly via the valve, to supply the fluid to the third coupling and, optionally, also to the electric motor. The fluid is then preferably returned to a reservoir or tank that provides the fluid. Preferably, the reservoir is designed, in contrast to a reservoir in the aforementioned hydraulic systems, such that the displacement volume of the now-omitted pump is compensated, for example, by an additional displacement element.In particular, the valve is designed to prioritize the supply of medium to the first and second couplings, and to supply medium to the third coupling only when no medium flow is required for the first and second couplings. Preferably, the pump is operatively connected to an electric motor, which is particularly speed-controlled. This allows the pump's power output, and thus the medium flow rate, to be advantageously adjusted.

[0013] Particularly preferred is the provision of at least a second and a third hydraulic line, each connected to one of the devices. This provides a particularly advantageous means of supplying the respective devices with medium as needed.

[0014] According to a preferred embodiment of the invention, the valve is designed such that, in a first switching position of the valve, the medium flows through the second hydraulic line to the first coupling, particularly only to the first coupling; that, in a second switching position of the valve, the medium flows through the first hydraulic line first to the third coupling and then to the second drive motor, particularly only first to the third coupling and then to the second drive motor; and that, in a third switching position of the valve, the medium flows through the third hydraulic line to the second coupling, particularly only to the second coupling. The selective flow through each coupling in the respective switching position offers the advantage that each coupling is supplied with medium as required.Therefore, a separate media stream is provided for each coupling.

[0015] It is particularly preferred that the valve is a 5 / 3-way valve, preferably electrically actuated, with two inlets and three outlets, that each of the outlets is assigned to exactly one of the couplings, and that the two inlets are assigned to the at least one hydraulic pressure source, particularly a pump. This provides a particularly advantageous way of controlling the coolant flows to the respective couplings. Preferably, the valve is a spool valve or a rotary spool valve. Particularly preferred is the valve being electrically and / or electromagnetically actuated. For this purpose, the valve is preferably assigned an electrically and / or electromagnetic actuator. This allows the valve to be switched advantageously quickly to a desired switching position.

[0016] Alternatively, the valve is provided to be a 4 / 3-way valve, particularly an electrically actuated one, with one inlet and three outlets, with each outlet assigned to exactly one of the couplings, and the inlet assigned to at least one hydraulic pressure source, particularly a pump. This provides a particularly advantageous way to control the coolant flows to the respective couplings. Preferably, the valve is a spool valve or a rotary spool valve. Particularly preferably, the valve is actuated by an electric motor and / or electromagnetic actuator. For this purpose, the valve is particularly well-equipped with an electric motor and / or electromagnetic actuator. This allows the valve to be switched advantageously quickly to a desired switching position.

[0017] The drive module with the features of claim 12 comprises a first drive motor, in particular an internal combustion engine, a second drive motor, in particular an electric motor, and a transmission that can be coupled to or is coupled to the drive motors. It is characterized by the hydraulic system according to the invention. The advantages already mentioned also result from this.

[0018] Further advantages arise in particular from what has been described above and from the claims. The invention will now be explained in more detail with reference to the drawings. To this end, we show... Figure 1 shows a circuit diagram of a hydraulic system according to the invention, and Figure 2 shows a detailed view of the hydraulic system.

[0019] The Figure 1Figure 1 shows a circuit diagram of an advantageous hydraulic system 1 designed for use in a drive module of a motor vehicle. The hydraulic system 1 has a first clutch 2, a second clutch 3, and a third clutch 4.

[0020] The first clutch 2 and the second clutch 3 are assigned to a first drive engine (not shown), in particular an internal combustion engine, and the third clutch 4 to a second drive engine 28, in particular an electric machine, in order to optionally couple these with a transmission of the motor vehicle.

[0021] The hydraulic system 1 also includes a common hydraulic circuit for cooling and / or lubricating at least the clutches 2, 3, 4 and the second drive motor 28. The hydraulic circuit includes a pump 5 for pumping a liquid medium. An additional pump 6 is also provided, which is optional and is intended here to supply other components of the vehicle, not shown, with the medium.

[0022] The two pumps 5, 6 are arranged on a common shaft, which is driven by an electric motor 7. The electric motor 7 is preferably speed-controlled, so that the delivery rate of the pumps 5, 6 and the respective coolant flow rate depend on the speed of the electric motor 7.

[0023] The two pumps 5, 6 are connected via an intermediate suction filter 8 to a tank or reservoir 9, which serves as a storage container or sump for the medium, and in which the medium is preferably stored without pressure.

[0024] Furthermore, the hydraulic circuit has a controllable valve 10 located between the couplings 2, 3, 4 and the pump 5 for adjusting a cooling media flow at least for the couplings 2, 3, 4 and the second drive motor.

[0025] The valve 10 is configured as an electrically actuated 5 / 3-way valve with three outlets 11, 12, 13 and two inlets 14, 15. A first outlet 11 is assigned to the first coupling 2, a second outlet 12 to the second coupling 3, and a third outlet 13 to the third coupling 4. A first inlet 14 and a second inlet 15 are both assigned to the pump 5. According to an embodiment not shown, only one inlet is provided, which is assigned to the pump 5. The valve 10 is then configured as a 4 / 3-way valve.

[0026] The valve 10 therefore has three possible switching positions 16, 17, 18. In a first switching position 16 of the valve 10, the medium flows from the second inlet 15 to the first outlet 11 through a second hydraulic line 19 only to the first coupling 2.

[0027] In a second switching position 17 of the valve 10, the medium flows from the first inlet 14 to the third outlet 13 through a first hydraulic line 20, initially only to the third coupling 4 and then to the second drive motor 28. It is therefore intended that the medium flows through both the third coupling 4 and the second drive motor 28.

[0028] For this purpose, guide plates and cross-sectional changes are provided, for example, to divide and direct the flow of the cooling medium. In particular, the third coupling 4 is first partially supplied with a portion of the cooling medium flow, and subsequently the second drive motor 28.

[0029] Part of the cooling medium flow is specifically diverted and supplied only to the second drive machine 28, so that medium is supplied to the third coupling 4 and the second drive machine 28 as required.

[0030] In a third switching position 18 of the valve 10, the medium flows from the second inlet 15 to the second outlet 12 through a third hydraulic line 21 only to the second coupling 3.

[0031] After the medium has flowed through couplings 2, 3, 4 and the second drive motor 28, it is returned to reservoir 9, as described in the Figure 1 hinted at.

[0032] In the first hydraulic line 20, downstream, i.e., in the direction of the third coupling 4 and the second drive motor 28, a pressure relief valve 22 and then an orifice 23 are arranged as a module 29. Finally, further downstream, a throttle 30 formed by hydraulic lines leading to the coupling 4 and the second drive motor 28 is arranged.

[0033] The pressure relief valve 22, the orifice 23, and the throttle 30 are components of an advantageous device 31 of the hydraulic system 1 and, as such, are designed to adjust the volume flow of the medium to the third coupling 4 as a function of the medium's temperature, as described above. The pressure relief valve 22 discharges excess medium back into the reservoir 9 and is designed as a poppet valve.

[0034] The Figure 2 Figure 1 shows a detailed view of module 29 in the second flow path 20, the flow direction of which is indicated by an arrow. The medium flows through an inlet opening 24 into a region 25. Above region 25 is the pressure relief valve 22, designed as a poppet valve.

[0035] A valve disc 26 of the pressure relief valve 22 seals the area 25 as long as the force resulting from the pressure exerted on the valve disc 26 by the medium is less than the force exerted on the valve disc by the spring force of a spring element 27, which is arranged on the side of the valve disc 26 facing away from the area 25.

[0036] If the pressure exerted by the medium is greater than the pressure exerted by the spring element 27 according to the spring force, the valve disc is displaced so that excess medium flows through the opening thus created into the pressure relief valve 22, which in turn is fluidically connected to the reservoir 9 as described above, so that the medium flows back into the reservoir 9.

[0037] Further along the second flow path 20, the aperture 23 is visible. In this case, it has a constant flow cross-section and serves as an outlet opening for the medium from area 25.

[0038] Downstream of the orifice 23, a tubular adapter element 32 is arranged as part of the throttle 30 in the first hydraulic line 20, wherein the adapter element 32 fluidly connects the device 31 with the hydraulic lines leading to the coupling 4 and the second drive motor 28.

[0039] The adapter element 32 has a first open end 33 with a first cross-section, associated with the orifice 23, and a second open end 34 with a second cross-section, associated with the hydraulic lines. In this case, the second cross-section is smaller than the first. The adapter element 32 has a continuously decreasing cross-section along its longitudinal extent, i.e., along the flow direction, and is therefore conical in shape.

[0040] By appropriately selecting the second cross-section and the geometric design of the adapter element 32, a conveniently simple adaptation of the device 31 to hydraulic lines with corresponding cross-sections is ensured, and an advantageous additional possibility of influencing a throttling section and thus the properties of the throttle 30 is created. The throttle 30 can therefore be advantageously adapted to the cooling and / or lubrication requirements of the clutch 4 and the second drive motor 28. REFERENCE MARK LIST:

[0041] 1 Hydraulic system 2 First coupling 3 Second coupling 4 Third coupling 5 Pump 6 Additional pump 7 Electric motor 8 Suction filter 9 Reservoir 10 Valve 11 First outlet 12 Second outlet 13 Third outlet 14 First inlet 15 Second inlet 16 First switching position 17 Second switching position 18 Third switching position 19 Second hydraulic line 20 First hydraulic line 21 Third hydraulic line 22 Pressure relief valve 23 Orifice plate 24 Inlet opening 25 Area 26 Valve plate 27 Spring element 28 Second drive motor 29 Module 30 Throttle 31 Device 32 Adapter element 33 First end 34 Second end

Claims

1. Device (31) for a hydraulic system (1), in particular of a motor vehicle, having a first hydraulic line (20) for connecting a hydraulic pressure source to at least one component to be cooled and / or lubricated, wherein a pressure relief valve (22) is associated with the first hydraulic line (20), which pressure relief valve has a reservoir connection and connects the first hydraulic line (20) to the reservoir connection when the hydraulic pressure in the first hydraulic line (20) exceeds a predetermined limit value, wherein a throttle (30) is arranged or formed in the first hydraulic line (20) downstream of the pressure relief valve (22), characterised in that an orifice (23) is arranged in the first hydraulic line (20) downstream of the pressure relief valve (22) and upstream of the throttle (30).

2. Device according to claim 1, characterised in that the device comprises the at least one component to be cooled and / or lubricated, and the component or at least one of the components is a clutch (2, 3, 4) and / or a drive engine (28) for a motor vehicle.

3. Device according to one of the preceding claims, characterised in that the pressure relief valve (22) is designed as a seat valve.

4. Device according to one of the preceding claims, characterised in that the pressure relief valve (22) and the orifice (23) are formed as a single module (29).

5. Device according to one of the preceding claims, characterised in that a tubular, and in particular also conical, adapter element (32) is arranged downstream of the orifice (23) as part of the throttle (30) in the first hydraulic line (20).

6. Hydraulic system (1) having at least one component to be cooled and / or lubricated, and a hydraulic circuit for cooling and / or lubricating the component, wherein the hydraulic circuit comprises at least one hydraulic pressure source, in particular pump (5), for conveying a liquid fluid, characterised by a device (31) according to one of claims 1 to 5, which comprises the first hydraulic line (20) and which is connected to the hydraulic pressure source on the one hand and to the at least one component on the other.

7. Hydraulic system (1) according to claim 6, for a drive module of a motor vehicle, characterised in that the hydraulic system (1) comprises at least one first clutch (2), a second clutch (3), and a third clutch (4) as components to be cooled and / or lubricated, that the first clutch (2) and the second clutch (3) are associated with a first drive engine, in particular an internal combustion engine, and the third clutch (4) is associated with a second drive engine (28), in particular an electric machine, in order to selectively couple these to a gearbox of the motor vehicle, that the hydraulic circuit is configured for cooling and / or lubricating at least the clutches (2,3,4) and the second drive engine (28), and that the hydraulic circuit comprises at least one controllable valve (10), interposed between the clutches (2,3,4) and the hydraulic pressure source, in particular pump (5), for setting a flow of fluid at least to the clutches (2, 3, 4) and the second drive engine (28).

8. Hydraulic system according to claim 7, characterised by at least a second hydraulic line (19) and a third hydraulic line (21), each of which is connected to one of the components.

9. Hydraulic system according to claim 8, characterised in that the valve (10) is configured such that in a first switch position (16) of the valve (10) the fluid flows through the second hydraulic line (19) to the first clutch (2), in particular only to the first clutch (2), that in a second switch position (17) of the valve (10) the fluid flows through the first hydraulic line (20) to the third clutch (4) first and subsequently to the second drive engine (28), in particular only to the third clutch (4) first and subsequently to the second drive engine (28), and that in a third switch position (18) of the valve (10) the medium flows through the third hydraulic line (21) to the second clutch (3), in particular only to the second clutch (3).

10. Hydraulic system according to one of claims 8 and 9, characterised in that the valve (10) is a, in particular electrically actuated, 5 / 3-way valve, having two inlets (14, 15) and three outlets (11, 12, 13), that exactly one of the outlets (11, 12, 13) is associated with exactly one of the clutches (2, 3, 4), and that the two inlets (14, 15) are associated with the at least one hydraulic pressure source, in particular pump (5).

11. Hydraulic system according to one of claims 8 and 9, characterised in that the valve (10) is a, in particular electrically actuated, 4 / 3-way valve having an inlet (14) and three outlets (11, 12, 13), that each one of the outlets (11, 12, 13) is associated with exactly one of the clutches (2, 3, 4), and that the inlet (14) is associated with the at least one hydraulic pressure source, in particular pump (5).

12. Drive module for a motor vehicle, having a first drive engine, in particular an internal combustion engine, a second drive engine (28), in particular an electric machine, and a gearbox which can be or is coupled to the drive engines, characterised by a hydraulic system (1) according to one of claims 6 to 11.

Images